October / November 2025

“The pre-harvest component is a critical phase for pathogen establishment,” says Dr Johan Fourie, postharvest pathologist at ExperiCo Agri-Research Solutions. “The source of inoculum is in the vineyard – that’s where the pathogen establishes.”

Fungi are responsible for most postharvest decay. Plant-pathogenic fungi can thrive on all sorts of organic material in the vineyard, producing spores that land on bunches. Growers mitigate the risk of postharvest decay by integrated management practices that include removing organic material, maintaining open canopies, and applying fungicides.

“The primary purpose of packaging is to maintain fruit quality – to deliver the best quality to our markets,” says Dr Johan Fourie, Postharvest Pathologist at ExperiCo Agri-Research Solutions. “We need to re-establish confidence in South African table grapes.”

To better understand how various packaging components and environmental conditions influence table-grape quality, the ExperiCo team has been running a three-year SATI-funded project. So far, they have studied the interactions between bunch carriers, liners, and SO2-release systems.

Wingerdkundige dr. Janéne Strydom van die LNR Infruitec-Nietvoorbij het onlangs ’n SATI-befondsde projek voltooi waarin sy verskillende besproeiingsbehandelings in wingerde met en sonder oorhoofse plastiek getoets het.

“Die weerpatrone in die areas waar mense met tafeldruiwe boer is besig om te verander,” sê Strydom. “Die doel van hierdie projek was om te kyk hoe wingerdstokke op verskillende klimaatskondisies reageer.”

On the first Tuesday in June 2025, more than 300 members of the deciduous-fruit industry gathered at the Lord Charles Hotel in Somerset West for the opening of the Hortgro Science Research Showcase. The impressive growth of this event testifies to the value that growers, technical advisers, and other stakeholders place on industry-funded research.

Pitting is a postharvest defect characterised by indentations on the shoulders or sides of cherries. Not to be confused with the lenticel-related pitting disorders of apples, pitting in cherries is a response to bruising caused by pre- and postharvest mechanical damage to the flesh. The skin is unbroken but sunken due to the collapse of the underlying tissues.

Mulch has much to commend it. Organic material layered on the soil retains moisture and suppresses weeds while slowly adding organic carbon to the soil. Many growers also believe that mulches reduce the impact of soil-borne pests and diseases. But is this true?

Mexican apple grower and Unifrut president Mauricio González recently visited SA to attend the Hortgro Research Showcase and accompany the APAL international tour of our orchards. His take-home message? Mexico and SA have a lot in common.

Orchard profitability starts – and sometimes ends – when a grower decides what to plant. But choosing the best option can be challenging, given the complex interactions between cultivars and climate in a world where the weather is more unpredictable than ever.

South Africans have a long history of visiting apple and pear growers and researchers in Australia. This year, we reciprocated by hosting a predominantly Australian group undertaking an international tour of South African orchards.

We further explore the outcomes of our trials that were done to determine suitable Valencia cultivars on Swingle citrumelo (SC) and US-812 (SxB) citrandarin rootstocks for an intermediate citrus production area.

In the SA Fruit Journal Aug/Sep ’25 edition, we shared results relating to Jasi Valencia and Kobus du Toit Late Valencia selections. Now, we will look at Late Valencia, McClean SL Valencia and Midknight Valencia and conclude on the suitability of these Valencia selections.

Given the strict market requirements when it comes to fruit flies, considerable effort is undertaken to suppress their populations in citrus orchards. Protein bait sprays, which are recommended for their effectiveness, are more commonly used than other protein bait application techniques such as bait stations and mass trapping. In addition to baiting, orchard sanitation is essential, and further suppression can be achieved using male-targeted attract-and-kill products.

Thrips management During October and November citrus fruit is highly susceptible to damage from citrus thrips. Therefore, orchards should be scouted at least once a week for this pest, being sure to look under the sepals. Citrus thrips larvae cause more serious damage than adult thrips. Therefore, low numbers of adults in the absence of larvae may not require immediate intervention. The intervention threshold for citrus thrips larvae on fruit is 2% for the first four weeks after petal fall, 3% for five to six weeks after petal fall, then 4% for seven to eight weeks after petal fall. These thresholds can be roughly doubled if the population comprises mostly adults.